In the dogfight between the mobile industry’s two titans, Apple and Google, it’s sometimes easy to overlook the fact that although the iPhone and iPad dominate on the hardware side, the Android operating system is used on far more devices.

Actually, according to Reuters, Google CEO Eric Schimdt believes that there are four times the number of Android devices than iOS out there, and that within a year as many as 1 billion mobile device worldwide will be running Android.

For perspective, that’s more than thrice the population of the United States and accounts for about 14% of all the world’s people, which indicates the incredible scale of the Apple vs. Google fight. Indeed, Schimdt calls it the “defining fight” of the industry.

Jobs and Schmidt having coffee in 2010 (Image credit: Gizmodo)

In retrospect, it’s somewhat incredible that these two companies ended up duking it out in the same markets. Apple, an innovative hardware maker, and Google, which made the Internet search engine a daily part of our lives, started out working in completely unrelated market segments. Over the years, of course, both gravitated toward the mobile market. Arguably, the conflict kicked up in earnest when Google debuted the Android operating system, which Steve Jobs famously felt to be a betrayal and an act of aggression.

Although the two companies worked together even as they competed, the two mobile platforms are further and further divorced from one another; for example, Apple ditched Google-owned YouTube in iOS 6 and built its own map app so it could end its reliance on Google Maps (which hasn’t gone well so far).

As the stakes get higher, the fight will intensify, and consumers will no doubt reap the benefits in the way of even more fantastic products.